1. Field of the Invention
This invention relates to a cutting apparatus with a light-emitting unit for alignment of a workpiece during a cutting operation.
2. Description of the Related Art
FIG. 1 illustrates a conventional cutting apparatus 10 that includes a base 11 adapted to receive a workpiece 100 thereon, a blade-holding arm 12, a blade 13 mounted rotatably on the blade-holding arm 12 through an axle, and a light-emitting unit 17 that is secured to one side of the axle so as to be co-rotatable with the blade 13. The light-emitting unit 17 includes a disc-shaped housing that is formed with a hole 171, a laser-emitting member 172 mounted in the housing for projecting light through the hole 171 and for generating an image line on the workpiece 100 when the light-emitting unit 17 rotates with the blade 13, and a battery 173 electrically connected to the laser-emitting member 172. The image line is to be constantly aligned with a cutting line marked on the workpiece 100 by the user during a cutting operation. The workpiece 100 is to be cut into two pieces. Only one of the two pieces is desired, whereas the other one is normally discarded. For the sake of convenience and cutting precision, the desired piece is to be disposed at the same side of the blade 13 as the image line. For instance, if the light-emitting unit 17 is mounted on the left side of the blade 13 (see FIG. 1), the image line formed on the workpiece 100 will be disposed at the left side of the blade 13, and the orientation of the workpiece 100 relative to the blade 13 should be arranged in such a manner that the desired piece is disposed at the left side of the blade 13. Accordingly, if the desired piece is disposed at the right side of the blade 13, it would be inconvenient and difficult for the user to align the workpiece 100 during the cutting operation. Moreover, since the light-emitting unit 17 is co-rotatable with the blade 13, the only way to supply power to the blade 13 is with the use of the battery 173. One disadvantage arising from replacement of the battery 173 is that the light-emitting unit 17 is required to be detached from the axle. If the laser-emitting member 172 is to be electrically connected to an AC power supply through a wire, it is relatively difficult to prevent twist of the wire during rotation of the blade 13.